This invention relates generally to program controllers for machines whose operation may involve any one of a number of distinct cycles or programs and more particularly concerns improved indexing and program selection apparatus suitable for use in commercial or institutional laundry machines.
It is typical in existing laundry machines for controllers to have a manually rotatable dial marked so that various sectors of the dial identify various distinct wash programs, formulas, or cycles. Such dials are often fixed to rotatable shafts on which a plurality of cams engage a gang of individual switches for controlling various mechanisms and subsystems within the machine. After the dial is manually rotated to the operator-selected sector, a timer motor which drives the dial shaft and cams through that section is engaged. In this manner, the steps defined by portions of the cams in that sector are performed by the machine. In a machine having a number of special purpose cycles, some of which may involve addition of special additives to deal with hard-to-remove stains or other environmental conditions, it is particularly important that the machine perform exactly the desired program. Often the omission of one step from a cycle or the inclusion of an unwanted step or additive may render the desired program ineffective or even harmful to the material being laundered. Since the program is defined by manual selection of a particular dial sector, errors of this type are likely. Another disadvantage of conventional machines having a manually settable circular dial used for program selection is that the number of easily distinguishable programs available is significantly limited.
In addition, a number of manual controllers have program selection dials which operate independently of the mechanism for starting machine operation. With such machines it is quite possible to forget to select the proper program before actuating the machine. This will result in a repeat of the program previously selected.
The indexing and selection apparatus of the present invention overcomes these disadvantages in a system in which improved flexibility and an ability to select many distinct programs is combined with simplified controls which accurately and repeatably cycle through all steps defining a particular program without deletion or addition of unwanted steps.